With development of the Internet of Things, a wireless local area network designed for the Internet of Things has a good development prospect. A wireless video surveillance network is a specific application scenario of a wireless local area network designed for the Internet of Things.
In the standard IEEE 802.11ah of a wireless local area network designed for the Internet of Things, a frequency band from 779 MHz to 787 MHz of China is divided into eight 1-MHz channels, four 2-MHz channels, two 4-MHz channels, and one 8-MHz channel. According to a channel division method of 802.11ah, in China, a maximum channel bandwidth of a frequency band (the frequency band from 779 MHz to 787 MHz) of the Internet of Things lower than 1 GHz used for various control or sensor devices is only 8 MHz. In addition, in the wireless video surveillance network, a data rate of a high-definition video stream is relatively high. For example, in a high-definition video surveillance network, a data rate of a single terminal is 0.5 Mbps to 2.5 Mbps. Assuming that a quantity of terminals (Stations, STAs) in the wireless video surveillance network is 12, an aggregation throughput of the wireless video surveillance network may reach 30 Mbps. In addition, high-definition video stream compression coding is classified into two coding manners: fixed bit rate compression and variable bit rate compression. For the variable bit rate compression coding, a data rate is closely related to a change speed of monitored content, so that a video data rate presents an obvious dynamic change characteristic, thereby affecting network indicator parameters such as a throughput and a delay of the wireless video surveillance network.
An AP (Access Point) of a video convergence center in the wireless video surveillance network is responsible for receiving video stream data uploaded by each STA in the network. Because a wavelength value corresponding to the frequency band from 779 MHz to 787 MHz is relatively large, a multi-antenna technology is generally not used in a device of the wireless video surveillance network due to a limitation on device outline dimensions. When the AP performs, by using a single transceiver, networking on an 8-MHz channel according to the IEEE 802.11ah standard, due to a limited bandwidth, concurrently transmitting multiple high-definition video streams easily causes load of the network to reach a saturated state. When the load of the wireless video surveillance network approaches saturation, if a few STAs have to use a low-rate modulation and coding scheme due to deteriorated channel quality, a relatively long distance, and the like, an actual throughput of the wireless video surveillance network is less than service load, an average delay of the entire network is increased, and QoS (Quality of Service) requirements such as delays of all STAs cannot be met. For example, for the bandwidth of the 8-MHz channel, if a few STAs in the wireless video surveillance network can use only a QPSK (Quadrature Phase Shift Keying,) modulation manner, a data rate is only ¼ of a data rate of 64-QAM (Quadrature Amplitude Modulation), and these low-rate STAs significantly decrease an average throughput of the network and increase an average delay.